Campfire chip burner

ABSTRACT

A campfire burner is a self-container device that holds loosely-packed hardwood chips that function as the main fuel for the burner. The chip container is fabricated from a flammable material so that the entire burner burns to ash when used. A chimney and air vents are provided to direct air to the fuel. A fire starter may be provided to allow the camper to start the fire with a single match.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/909,660 filed Apr. 2, 2007; the disclosures of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention generally relates to combustible devices used to provide light and heat in an outdoor campfire setting. Specifically, the invention relates to a combustible burner used as fuel for a campfire.

2. Background Information

Numerous states now regulate the movement of firewood for campfires. These regulations are designed to limit the spread of wood-boring insects and worms (particularly the emerald ash borer). For example, the U.S. Department of Agriculture has quarantined a portion of Southeast Michigan wherein the movement of firewood is strictly regulated. Many regions in the Midwest have regulations limiting the transport of firewood. As such, popular camping areas can run out of firewood as campers gather wood that has fallen over the winter. These regulations have increased the cost of small bundles of campfire wood as its availability has decreased. The difficulty in obtaining inexpensive firewood leads many overnight campers to smuggle firewood into locations. Such smuggling is undesirable because of the infestation risk.

These regulations have increased the need for an alternative campfire device. The alternative campfire device must be transportable between different areas. The device most also be an acceptable alternative to a traditional campfire so that campers will readily substitute the alternative campfire device for smuggled firewood. Most overnight campers desire a small simple camp fire that lasts a short time after dusk. The campfire should be hot enough to cook a hot dog and roast marshmallows. Campers also desire a yellow flame while the fire is burning. The campers also desire glowing embers after the flames have diminished.

SUMMARY OF THE INVENTION

The invention provides a campfire chip burner that functions as a campfire when ignited. The burner is a self-container device that holds loosely-packed hardwood chips that function as the main fuel for the burner. The chips may be treated so that they will be approved by state regulators for movement into and out of firewood quarantine areas. The body of the burner is fabricated from a flammable material so that the entire burner burns to ash. This prevents damage to lawn equipment used at campgrounds. In situations where all of the chips do not burn, they may be spread about like mulch and will not damage equipment or degrade the camping area. A chimney directs air to the chips from the bottom of the burner. The location of the chimney helps to control the burn pattern of the burner. A starter may be provided to allow the burner to be started with a single match.

The chimney provides air to the center of the burner which encourages the wood chips in the center of the burner to burn faster than the outer chips. The chips tend to collapse inwardly as the center burns. Air vents defined by the upper portion of the sidewall help the upper portion of the fuel chips to burn. The combination of the chimney and vents provides a desirable burn where most of the flame is generated from the center of the burner at the beginning of the burn.

In one configuration, the container body (outer wall, bottom wall, and chimney) is fabricated from a paper-based cardboard. A portion of the body may be treated with a fire retardant that delays the combustion of that portion of the container. The fire retardant helps the body maintain a desirable shape while the hardwood chips burn.

In another configuration, the burner has a wooden bottom wall that defines air ducts leading to the bottom of the chimney. This configuration may rest directly on the ground when burned.

An alternative feature is the use of a chimney that increases in dimension toward the bottom of the burner.

The features described in the different configurations may be used in different combinations to achieve further configurations of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top perspective view of one configuration of the chip burner of the invention.

FIG. 2 is a bottom plan view of FIG. 1.

FIG. 3 is a plan view of one exemplary sidewall in a flat configuration before it is assembled.

FIG. 4 is a section view taken through the chimney of the burner along section line 4-4 of FIG. 1.

FIG. 5 is a top perspective view of another configuration of the chip burner of the invention.

FIG. 6 is a bottom plan view of FIG. 5.

FIG. 7 is a section view taken through the chimney of the burner along section line 7-7 of FIG. 5.

FIG. 8 is a section view similar to FIG. 7 taken through the chimney of a further configuration of the burner.

Similar numbers refer to similar parts throughout the specification. The drawings are not to scale.

DESCRIPTION OF EXEMPLARY CONFIGURATION

Different configurations of a campfire chip burner are indicated generally by the common reference numeral 10 in the following description and in the accompanying drawings. Each burner 10 may be used as a self-container campfire for light, heat for cooking, and glowing embers for roasting. The overall size of burner 10 and the moisture content of the fuel dictate the burn intensity and burn time of burner 10. One desirable configuration of burner 10 has 1½ hour burn time followed by a 2 hour ember glow. Burner 10 is fueled with loosely packed wood chips 22 that have been approved for transportation into and out of geographic areas under firewood limitations. When packaged for sale, burner 10 is a self-container unit that may be lit with a single match. Lighter fluids or additional kindling are not needed. Burner 10 is thus desirable for overnight campers or for backyard marshmallow roasting because it is convenient and self-contained.

In one exemplary configuration, chip burner 10 includes a body having a sidewall 12, a bottom wall 14, and a chimney 16. Chimney 16 has an open top and an open bottom and defines an open air duct. Chimney 16 may have any of a variety of cross sectional shapes. A circular shape is depicted as an example. Chip burner 10 may include an optional top wall 18. Top wall 18 may be entirely closed, define an opening 20 (as shown), or may be eliminated. When top wall 18 is eliminated, burner 10 may be wrapped in plastic (such as a plastic bag, a shrink wrap, or a stretch wrap) that keeps the fuel disposed in the body of burner 10. The plastic wrap is also useful for keeping moisture out of burner 10. When top wall 18 is entirely closed, it may be removed prior to lighting burner 10. A line of severance 19, such as the perforated tear line shown in FIG. 5, may be used to allow the user to tear away the middle portion of top wall 18 from the upper fold-over tabs of sidewall 12. Wall 18 may be thrown away in a trash receptacle or may be burned after burner 10 is lit.

Chimney 16 and at least a portion of sidewall 12 may be fabricated from a paper-based cardboard material. In the exemplary configurations, sidewall 12, top wall 18, and chimney 16 are fabricated from a paper-based material such as a corrugated cardboard with a pair of liner board sandwiching a corrugation layer. The entire or portions of sidewall 12 may be treated with a fire retardant that helps sidewall 12 burn slower to allow it to maintain the structure of burner 10 during the beginning of the burn time. Eventually, the treated portions of burner will burn to ash. In one configuration, only the outer liner board of sidewall 12 is treated with the fire retardant. In another configuration, both liners of sidewall 12 are treated. Chimney 16 also may be treated with a fire retardant that slows its combustion. In one exemplary configuration, the entire length of chimney 16 is treated with the retardant while only the lower portion (½ or ⅓ or ¼) of sidewall 12 is treated. The treatment of the lower portion of sidewall 12 allows sidewall 12 to retain the chips as they burn down.

Chimney 16 supplies air to the center of burner 10 so that the entire center portion of burner 10 is quickly lit from a flame that starts on the top of burner 10 and ignites the top of chimney 16. The bottom of chimney 16 may extend out from below the bottom surface of bottom wall 14 as shown in FIG. 4. Extending chimney 16 past bottom wall 14 helps maintain air flow to the fuel chips when chimney 16 is burning and helps keep the chips in burner 10. In FIGS. 7 and 8, the bottom of chimney 16 is flush with or inset above bottom wall 14. In these configurations, a portion of bottom wall 14 may be fabricated from wood such as plywood. A thick wooden bottom wall 14 stabilizes burner 10 and provides a combustible bed for the embers at the end of the initial burn. Bottom wall 14 may be configured to help maintain the airflow to the fuel chips even when chimney 16 has burned and collapsed.

In the exemplary configuration of burner 10 depicted in the drawings, sidewall 12 is octagonal (in cross section) with tabs on its top and bottom to fold over and be glued to top wall 18 and bottom wall 14. Sidewall 12 may be provided in a variety of cross sectional configurations including square or rectangular, hexagonal, and circular.

A plurality of loosely packed wood chips 22 function as the main fuel for the burner. The chips may be hardwood wood chips. The chips do not need to be encased in wax or other substances to aid the combustion. The wood chips may be heat treated to eliminate the risk of wood boring insects and worms. Chips 22 are disposed in the space defined inside sidewall 12, above bottom wall 14, and radially outwardly of chimney 16. Chips 22 desirably have retained moisture to slow the burn of burner 10. A wood chip moisture content, by weight, of between 4% and 20% is desirable. In one exemplary configuration, a moisture content, by weight, of between 6% and 10% has been found to function well in combination with a sidewall height of 18 inches with a circumference of 52 inches. Smaller versions of the body of burner are also useful for faster burn times.

Feet 24 may be disposed on the bottom of burner 10 to stabilize the burner while it burns and to allow air to flow into the bottom of chimney 16. Feet 24 may be made from a combustible material such as strips of wood. Feet 24 may also be fabricated from a cardboard. In another exemplary configuration, sidewall 12 may be configured to integrally function as feet 24 to keep airflow to the inlet of chimney 16. In the configuration, portions of sidewall 12 extend down past bottom wall 14 to function as feet.

A different configuration is shown in FIGS. 6 and 7 wherein bottom wall 14 includes a piece of wood (such as three-quarter inch thick plywood) with at least one air duct 30 defined within bottom wall 14. In this configuration, burner 10 rests direct on bottom wall 14 and air is drawn into chimney 16 through ducts 30. The wooden portion of bottom wall 14 retains its structure for most of the burn such that air can be drawn through duct 30 for most of the burn. In the exemplary configuration, a plurality of ducts 30 are defined by bottom wall 14. Each duct 30 provides fluid communication to the inlet of chimney 16. Each duct 30 is substantially perpendicular to chimney 16. Each duct 30 extends in a direction from chimney 16 toward sidewall 12. Although ducts 30 are straight in the drawings, they may be disposed in an angled or swirled arrangement.

In the FIGS. 6 and 7 configurations, bottom wall 14 defines a central cavity 32 in fluid communication with the bottom of chimney 16 and in fluid communication with each of ducts 30. Bottom wall 14 also may include a cardboard disc 34 that is located on top of the wooden portion of bottom wall 14 to prevent chips 22 from falling into cavity 32. In FIG. 8, cardboard portion 34 of bottom wall 14 is not needed because the bottom of chimney 16 engages the wooden portion of bottom wall 14. The direct engagement may be achieved by reducing the size of or eliminating cavity 32 or by increasing the size of the bottom of chimney 16.

A fire starter 26 may be provided at the top of chips 22 so that the user may start the entire fire with a single match. Fire starter 26 may be a separate element such as a wax ring with a wick (FIGS. 1-4) or loose kindling (FIG. 7). Fire starter 26 may be integrated into the body of burner 10 such as at the top of chimney 16.

Burner 10 may be provided to the user contained in a plastic bag or plastic shrink wrap layer as described above. The plastic may be biodegradable or burnable. The plastic helps to maintain the proper moisture content of the chips. The user may purchase burner 10 in such packaging and transport burner 10 to the location of the campfire. The user removes the wrapping before starting the fire. Once the fire is started, the chips at the top of the burner 10 will ignite and burn. Air is drawn up through chimney 16 by the heat. As the fire spreads, the top of sidewall 12 and chimney 16 are consumed and the fire burns lower. The fire will burn into the center of the fuel chips because of the air being drawn up through chimney 16. This action leads to a strong flame that mimics a traditional campfire. Air vents 28 defined by sidewall 12 allow air to be drawn in amongst the wood chips disposed closer to the sidewall 12 to provide even burning. Vents 28 may be disposed about a quarter of the sidewall height from the top. Sidewall 12 maintains the packed configuration of the chips until the fire burns almost entirely down to bottom wall 14. Burner 10 thus provides a good flame shape and height throughout its entire burn. The size and moisture content of burner 10 may be adjusted to provide different burn and ember times. In one configuration, the burn is about 90 minutes followed by a period of about 30 minutes of hot embers.

Burner 10 provides the benefit of a camp fire flame in combination with a hot ash pile for cooking or roasting. Burner 10 complies with park and state regulations related to the transport of firewood. Burner 10 burns to ash. In the event the burner does not completely combust (i.e.: heavy rain downpour extinguishes the fire), then the resulting unburned contents may be spread as mulch (with the cardboard being burned or disposed of in the trash). Nothing in burner 10 will damage mowers that are used to cut the grass at campgrounds. Burner 10 eliminates the need to police campgrounds for partially burned logs that can damage mowing equipment and are unsightly.

In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed.

Moreover, the description and illustration of the invention is an example and the invention is not limited to the exact details shown or described. 

1. A campfire chip burner comprising: a body having a sidewall, a chimney, and a bottom wall; the chimney defining an air duct that allows air to be drawn into the chimney through the bottom wall; the body defining a chamber inwardly of the sidewall, above the bottom wall, and outwardly of the chimney; a plurality of loose wood chips disposed in the chamber; and the body being combustible.
 2. The burner of claim 1, wherein the chimney extends below the bottom wall of the body.
 3. The burner of claim 1, wherein at least the sidewall of the body is fabricated from cardboard.
 4. The burner of claim 3, wherein at least a portion of the sidewall is treated with a fire retardant.
 5. The burner of claim 1, wherein the bottom wall of the body defines at least one air supply duct in fluid communication with the chimney.
 6. The burner of claim 5, wherein a portion of the bottom wall is fabricated from wood; the wooden portion of the bottom wall having an upper surface and a lower surface; the air supply duct being open to the lower surface of the wooden portion of the bottom wall.
 7. The burner of claim 6, wherein the bottom wall defines a central cavity in fluid communication with the chimney.
 8. The burner of claim 7, wherein the bottom wall includes a member disposed above the wooden portion of the bottom wall; the member being combustible; the member defining a portion of the central cavity.
 9. The burner of claim 1, wherein the sidewall of the body has an upper portion and a lower portion; the upper portion of the sidewall defining a plurality of air vents.
 10. The burner of claim 1, wherein the moisture content of the chips is between 5% and 20%.
 11. The burner of claim 10, wherein the moisture content of the chips is between 5% and 10%.
 12. The burner of claim 1, further comprising a fire starter.
 13. The burner of claim 1, further comprising at least one layer of plastic disposed substantially around the body.
 14. The burner of claim 1, wherein the chimney has an upper portion and a lower portion; the lower portion of the chimney being wider than the upper portion of the chimney.
 15. A campfire chip burner comprising: a body having a sidewall, a bottom wall, a top wall, and a chimney; the body carrying a plurality of loose wood chips; at least a portion of the top wall being removable from the body to expose a portion of the wood chips; the chimney defining an air duct having an inlet that opens through the bottom wall of the body; and the bottom wall of the body defining at least one air supply duct in fluid communication with the inlet of the chimney.
 16. The burner of claim 15, wherein at least a portion of the sidewall is treated with a fire retardant.
 17. The burner of claim 15, wherein at least a portion of the bottom wall has a wooden body; the bottom wall having an upper surface and a lower surface; the air duct being defined by the wooden body of the bottom wall and being open to the lower surface of the wooden body.
 18. The burner of claim 17, wherein the wooden body of the bottom wall defines a portion of a central cavity in fluid communication with the inlet of the chimney.
 19. A campfire chip burner comprising: a body having a sidewall, a bottom wall, a top wall, and a chimney; the body carrying a plurality of loose wood chips; the sidewall being fabricated from a corrugated cardboard; the sidewall having an upper portion and a lower portion; the upper portion of the sidewall defining a plurality of air vents; at least a portion of the sidewall being treated with a fire retardant; at least a portion of the top wall being removable from the body to expose a portion of the wood chips; the chimney defining an air duct having an inlet that opens through the bottom wall of the body; the bottom wall of the body defining a plurality of air supply ducts in fluid communication with the inlet of the chimney; and at least a portion of the bottom wall having a wooden body; the wooden body of the bottom wall having an upper surface and a lower surface; the plurality of air ducts being defined by the wooden body of the bottom wall and being open to the lower surface of the wooden body.
 20. The burner of claim 19, wherein the wooden body of the bottom wall defines a portion of a central cavity in fluid communication with the inlet of the chimney. 